This invention relates, generally, to communication networks and, more particularly, to housings that protect components contained therein from inhospitable environmental surroundings.
As broadband networks continue to move from the experimental realm to the order of the day for network and service providers, the competition-driven need for providers to reduce costs of implementation increases proportionally. Plain Old Telephone Service (xe2x80x9cPOTSxe2x80x9d) has traditionally relied on copper twisted-pair cabling to deliver telephony signals. Similarly, community Access Television (xe2x80x9cCATVxe2x80x9d) has traditionally relied on metallic coaxial (xe2x80x9ccoaxxe2x80x9d) cabling to deliver video signals. Currently, as the frontier of optical fiber networks delivering broadband signals expands past more and more residential homes, technologies are continually emerging that allow providers to continually increase the number of subscribers reached by their networks. These technologies include, for example, active fast and gigabit Ethernet components.
Providers delivering signals over POTS and CATV networks have been able to use electronic amplifiers placed along a twisted pair or coax cable to boost a signal carried thereon depending on the distance the signal must travel. Optical network providers have used passive optical networks (xe2x80x9cPONSxe2x80x9d), which use splitters in a distribution network to take a signal from a single waveguide and split out a plurality of signals for sending to a corresponding plurality of different subscribers. Unlike the active components of the electronic amplifiers used in a POTS or CATV network system, the PONS splitters use primarily passive components, such as mirrors. However, in order to increase subscriber density served by a single fiber, optical network providers are increasingly using active components in the field. These active components may include electronic amplifies similar to PONS and CATV systems, but may also require optical signal interface components, such as, for example, lasers.
Although the heat generated by the active electrical and electronic components of the active optical devices may be of magnitude similar to that of the active components of a POTS or CATV system, the optical lasers produce substantially more heat than these components. Thus, since it is desirable to house the electrical, optical and laser components in a single housing, more heat is typically produced in a single enclosure. Since heat is an enemy of active components, the housing that encloses the components should be designed to allow removal of heat away from the active components at a high enough rate to eliminate destructive temperature levels at the discrete components of a particular node or subscriber premise equipment, for example.
However, while the heat transfer rate should be high, the enclosure should protect its internal components from the potential harshness of the outdoors. The internal components should be protected from weather, such as extreme cold and heat, as well as precipitation. In addition, insects and small animals should be prevented from entering the enclosure. All the while costs should be restrained.
Various enclosure designs have been made in attempting to provide the foregoing features. For example, U.S. Pat. No. 6,401,463 to Dukham et al. discusses an enclosure using a vortex tube, a compressed air source and a forced draft fan. U.S. Pat. No. 6,400,567 to McKeen et al. discusses an enclosure having at least two separate airflow paths with a baffle separating them. U.S. Pat. No. 5,960,592 to Lilienthal, II et al. discusses an enclosure comprising double walls which can be filled with concrete. U.S. Pat. No. 5,812,373 to Hwang discusses an enclosure using a heat conducting material to remove heat from an inner container. U.S. Pat. No. 5,912,803 to Dahl et al. discusses an enclosure having at least two separate airflow paths with a baffle separating them. And, U.S. Pat. No. 5,267,122 to Glover et al. discusses an enclosure that uses metallic fins that sealingly penetrate the enclosure to essentially wick heat from inside the enclosure to the outside.
While the foregoing references purport to protect components from the environment and remove heat at the same time, they are complex; thus, costly. Therefore, there is a need in the art for an inexpensive enclosure for protecting internal components from the environment while providing ample cooling to the active components contained therein.
An objective of the invention is to use an environmentally hardened housing to isolate internal components, such as, for example, an optical switch having active components, from an outdoor or underground environment.
It is another objective to provide ample cooling for the active components contained within the enclosure. These components may include active electrical and electronic devices, as well as lasers, which typically produce large amounts of heat. An aspect facilitates the required cooling while the aforementioned environmental protection is retained.
It is yet another objective to provide such an enclosure that is simple to manufacture and install in the field, thus minimizing costs.
Generally described, an aspect comprises a formed enclosure, the enclosure comprising front and back opposing walls, left and right opposing walls and a roof. The walls and roof, which may be rectangular, for example, may be connected together in a typical box fashion such that the roof is substantially parallel to the ground and the walls are perpendicular thereto. The enclosure may also include a floor opposing the roof and parallel thereto.
Each of the connected walls may define at least one bottom opening disposed in the wall proximate the floor. Each bottom opening may be rectangularly shaped with each short side of the opening being parallel and proximate a corner edge defined by the intersection of the wall and one of its adjoining walls, and each long side of the opening being parallel the floor.
Each wall may also define at least one top opening disposed in the wall proximate the roof. Each top opening or openings may be rectangularly shaped with each short side of the opening being parallel and proximate a corner edge defined by the intersection the wall and one of its adjoining walls, and each long side of the top opening being parallel to the floor and roof.
Precipitation may be deflected from each bottom opening by a louver sloping downwardly from a wall end to a distal end. Each top opening may be shrouded by a continuous overhanging cave that runs around the perimeter of the roof. Each opening may be covered by screen material designed to maximize airflow while preventing entry of insects and small animals through the openings into the enclosure. The enclosure may also comprise a strand mounting bracket for mounting the enclosure from an overhead strand.